The rapidly rising cost of packaging materials has prompted a reassessment of the closure requirements for certain liquid products distributed in industrial size containers such as five gallon cans and pails. Inasmuch as many liquid products, such as in the agricultural chemical field, are decanted rapidly in a single operation into a large vat or holding tank, the necessity for a conventional resealable pouring spout closure is questionable. Cost considerations indicate that a much simpler closure construction could just as well perform this function. Those particular container closure characteristics deemed to be of paramount importance in the above mentioned environment are firstly, the need for a heavy duty leakproof construction capable of withstanding severe abuse under varied shipping and use conditions. Secondly, the closure must be sufficiently tamperproof so as to adequately protect the container contents against undetected pilferage and substitution. Thirdly, it is important that the end user be able to gain access to, and readily decant, the entire container contents with a high degree of facility. A large pour opening that is exposed without the use of a tool or implement is most desirable. In addition to the above requirements, the provision of a very simple splash guard type of reclosure is sought for use in those instances where less than the entire pail contents are immediately poured out.